The C3 alcohols are useful as various industrial raw materials, etc. Among these C3 alcohols, diols are widely employed as raw materials for polymers and solvents. In particular, 1,3-propanediol (hereinafter occasionally referred to merely as “1,3-PD”), have been noticed as raw materials of polyesters and polyurethanes. Therefore, it has been recently demanded to develop processes for producing 1,3-PD in an efficient and inexpensive manner.
As the method for producing the 1,3-PD, there are conventionally known (1) a method in which ethylene oxide is hydroformylated to synthesize 3-hydroxypropanal which is then hydrogenated to produce the 1,3-PD, and (2) a method in which acrolein is hydrated to synthesize 3-hydroxypropanal which is then hydrogenated to produce the 1,3-PD.
However, in these conventional methods, the 1,3-PD must be produced by the two-step reactions and via 3-hydroxypropanal as a thermally unstable intermediate product, resulting in high production costs owing to deterioration in yield of the 1,3-PD. For this reason, it has been further demanded to develop a process for producing the 1,3-PD with low costs.
On the other hand, there are also known methods for hydrogenolysis of polyhydric alcohols such as, for example, glycerol, in which the glycerol is converted into 1,2-propanediol (hereinafter occasionally referred to merely as “1,2-PD”) and 1,3-PD in a one-step reaction. For example, as the hydrogenolysis methods, there are disclosed a method using a homogeneous catalyst containing tungstic acid and a metal component belonging to Group VIII of the Periodic Table (short-form Periodic Table) (for example, refer to Patent Document 1), a method using a homogeneous catalyst composed of a platinum-group metal complex and an anion source (for example, refer to Patent Document 2), and a method using a rhodium catalyst (for example, refer to Non-Patent Document 1 and 2).
Patent Document 1: U.S. Pat. No. 4,642,394
Patent Document 2: JP 2001-510816A
Non-Patent Document 1: Green Chem., 359, 6, (2004)
Non-Patent Document 2: Catalyst, vol. 49, No. 6, p. 438-441 (2007)